1. Field of the Invention
The present, invention relates in general to baking ovens. In particular, the present invention relates to an improved air flow system for small bakery rack ovens.
2. Description of the Related Art
Baking ovens for use in small bakeries or the bakery sections of grocery stores have been known for many years. A particularly widespread design is exemplified by U.S. Pat. No. 3,537,405 to Verhoeven. This design includes a baking chamber sized to receive a tall rack containing multiple layers of goods to be baked. The rack is wheeled into the chamber and thereby engages a lifting and rotating mechanism which lifts the rack slightly off of the floor of the baking chamber and rotates the rack during the baking cycle.
The oven includes a conventional burner and a blower system which channels a high velocity of heated air across the baking chamber in a relatively narrow channel in relation to the circle defined by the rotating outer corners of the rack. By this arrangement the goods which are closest to the corner of the rack will be closer to the source of hot air, and will thus be subjected to higher heat, but pass through this section only periodically. Those baked goods near the center of the rack will be subjected to less heat, but this heat will be substantially constant. By this arrangement the baked goods are of a uniform quality.
While the theory behind the above-described oven is sound, the application of this theory is quite difficult. To achieve truly uniform quality of baking, it is necessary to provide a substantially uniform flow of heated air across the baking chamber. This is difficult to achieve because the heated air has a tendency to enter the chamber at a higher volumetric rate at the beginning of the outlet grid (typically at the top of the chamber). Additionally, it is difficult to maintain a flow of air substantially uniform in the lateral direction, as the air flow tends to expand outward into a wedge shape. Both of these variations from the optimum air flow reduce the baking quality and thus the amount of salable goods produced.